The present invention relates to cellular concrete compositions which are strengthened by addition of polycarboxylic acids, and the method of making such compositions. More particularly the present invention relates to light-weight cellular concrete, the strength of which is improved by addition of polycarboxylic acids such as maleic and fumaric acid or their combined use with alkylene glycols such as ethylene glycol and/or nonionic surface active agents such as polyethylene glycol, and the method, in which cellular concrete is produced by mixing a cement mortar or paste with a bubbled frother solution containing polycarboxylic acids or together with alkylene glycols and/or nonionic surface active agents.
The light weight, heat insulation, fire resistance, and sound insulation of cellular concrete have allowed it to find a definite niche in the field of building materials.
The process for producing cellular concrete is generally divided into two: (1) to make a cement mortar foam in a form after mixing all the ingredients and (2) to mix a cement paste with a bubbled frother solution, followed by casting this cellular concrete paste into a form. The latter method is widely used since it can make it easy to manufacture the desired form of cellular concrete. However, this procedure has a difficulty to control the flow of aerated concrete slurry or to cause defoaming during the mixing.
For this reason, the use of surface active agents or decomposition products of keratin-type proteins as frother have been proposed. And also, Japanese Patent Publication No. 61-5673 provides processes in which cellular concrete is produced by addition of anionic surface active agents during or just after mixing a cement mortar with a bubbled, high-viscous frother solution. These methods, however, are also unsatisfactory since they do not give cellular concrete manufactures having a sufficient mechanical strength.